The BLANK specifier asks what type of blank control is in effect for a file. It takes the following form:
BLANK = blnk
blnk
Is a scalar default character variable that is assigned one of the following values:
| 'NULL' | If null blank control is in effect for the file |
| 'ZERO' | If zero blank control is in effect for the file |
| 'UNDEFINED' | If the file is not connected, or it is not connected for formatted data transfer |